我在程序中使用了apache http client lib。我为网络调用设置了连接超时和套接字超时。我的理解是，如果有连接超时，客户端没有到达后端服务器;如果存在套接字超时，则客户端到达后端服务器但服务器没有响应或非常慢。
我记录以下异常跟踪堆栈。如何判断哪个超时（连接或套接字）导致异常？谢谢！
java.net.SocketException: The operation timed out
at org.apache.harmony.luni.platform.OSNetworkSystem.connectStreamWithTimeoutSocketImpl(NativeMethod)
at org.apache.harmony.luni.platform.OSNetworkSystem.connectStreamWithTimeoutSocket(OSNetworkSystem.java:130)
at org.apache.harmony.luni.net.PlainSocketImpl.connect(PlainSocketImpl.java:247)
at org.apache.harmony.luni.net.PlainSocketImpl.connect(PlainSocketImpl.java:534)
at java.net.Socket.connect(Socket.java:1056)
at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:119)
at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:143)
at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:348)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)